Monthly Archives: April 2017

POWER PLANT: Two Westinghouse J30-WE-20 turbojet engines, rated at 725 kp each

PERFORMANCE: 479 mph at sea level

COMMENT: In early 1943, aviation officials at the United States Navy were impressed with McDonnell’s audacious XP-67 “Bat” project. McDonnell was invited by the Navy to cooperate in the development of a shipboard jet fighter, using an engine from the turbojets under development by Westinghouse Electric Corporation. Three prototypes were ordered on August 1943 and the designation XFD-1 was assigned. Under the 1922 United States Navy aircraft designation system, the letter “D” before the dash designated the aircraft’s manufacturer. The Douglas Aircraft Company had previously been assigned this letter, but the USN elected to reassign it to McDonnell because Douglas had not provided any fighters for Navy service in years.
McDonnell engineers evaluated a number of engine combinations, varying from eight 24 cm diameter engines down to two engines of 48 cm diameter. The final design used the two 48 cm engines after it was found to be the lightest and simplest configuration. The engines were buried in the wing root to keep intake and exhaust ducts short, offering greater aerodynamic efficiency than underwing nacelles and the engines were angled slightly outwards to protect the fuselage from the hot exhaust blast. Placement of the engines in the middle of the airframe allowed the cockpit with its bubble-style canopy to be placed ahead of the wing, granting the pilot excellent visibility in all directions. This engine location also freed up space under the nose, allowing designers to use tricycle gear, thereby elevating the engine exhaust path and reducing the risk that the hot blast would damage the aircraft carrier deck. The construction methods and aerodynamic design of the “Phantom”, as the aircraft was assigned, were fairly conventional for the time; the aircraft had unswept folding wings. Adapting a jet to carrier use was a much greater challenge than producing a land-based fighter because of slower landing and takeoff speeds required on a small carrier deck. When the first XFD-1was completed in January 1945, only one Westinghouse was available for installation. Ground runs and taxi tests were conducted with the single engine, and such was the confidence in the aircraft that the first flight on 26 January 1945 was made with only the one turbojet engine. During flight tests, the “Phantom” became the first naval aircraft to exceed 500 mph. With successful completion of tests, a production contract was awarded on March 1945 for 100 FD-1 aircraft. With the end of the war, the “Phantom” production contract was reduced to 30 aircraft, but was soon increased back to 60.
The first prototype was lost in a fatal crash on November 1945, but the second and final “Phantom” prototype was completed early the next year and became the first purely jet-powered aircraft to operate from an American aircraft carrier, completing four successful takeoffs and landings on 21 July 1946, from USS CV-42 “Franklin D. Roosevelt”. At the time, she was the largest carrier serving with the U.S. Navy, allowing the aircraft to take off without assistance from a catapult (Ref. 24).

POWER PLANT: Two Heinkel-Hirth HeS 011 turbojet engines, rated at 1,300 kp each

PERFORMANCE: 659 mph at 45,900 ft

COMMENT: In 1944, Focke-Wulf Aircraft Company projected three designs of a bomber using two Heinkel-Hirth He S 011 turbojets. These bombers were known under the unofficial designation “1000x1000x1000 Bomber-Projekt A”, Projekt B and Projekt C. The designation “1000x1000x1000” meant that the aircraft could carry a 1000 kg (2205 lbs) bomb load over a distance of 1000 km (621 miles) and at a speed of 1000 km/h (621 mph).
The second design under the Focke-Wulf internal designation Fw P.031 0239/10 “3×1000 Bomber, Projekt B” was of a flying wing layout. There was a small fuselage which held the cockpit and forward landing gear. The wing was swept back at 35 degrees and the fuel load in flexible tanks was carried ahead of the main wing spar. The engines and main landing gear were located behind the main wing spar. Two Heinkel-Hirth He S 011 jet engines each developing 1300 kg of thrust were fed by air intakes located in the wing leading edge near the wing roots. The wing tips were bent downwards to act as vertical stabilizers and contained small rudders. The ailerons also served as elevators and in addition small deflectors were mounted within the jet exhaust, one of the first uses of thrust vectoring. The main landing gear retracted inwards and the nose gear swung up and forward. A single pilot sat in the extensively glazed cockpit located in the extreme nose, and no armament was planned at this stage in the development. A 1000 kg bomb load could be carried in the internal bomb bay located in the center wing. Since these designs would have taken several years to complete, the end of the war ended all development (Ref.: 17).

COMMENT: In 1939 the Imperial Japanese Navy instructed the Kawanishi Aircraft Company to develop a two-seat high-speed reconnaissance floatplane, which was required to have sufficient performance to escape interception by land based fighters. It was planned to equip a new class of cruisers, intended to act as a flagship for groups of submarines operating six of the new floatplanes to find targets. Kawanishi designed a single-engine low-wing monoplane, powered by a 1,460 hp Mitsubishi MK4D Kasei 14 radial engine driving two contra-rotating two-blades propellers, the first installation of contra-rotating propellers produced in Japan, while a laminar flow airfoil section was chosen to reduce drag. It had a single main float under the fuselage and two stabilising floats under the wing. The stabilising floats were designed to retract into the wing, while the central float was designed to be jettisoned in case of emergency, giving a sufficient increase in speed to escape enemy fighters. It is noteworthy to mention that similar design was chosen by Kawabishi’s engineers for the new Kawanishi N1K1 “Kyofu” float seaplane fighter.
The first prototype of Kawanishi’s design, designated E15K1 in the Navy’s short designation system made its maiden flight on 5 December 1941. Five more prototypes followed during 1941-42. Problems were encountered with the retractable stabilising floats, resulting in several accidents when the floats could not be lowered for landing, and the system was eventually abandoned, with the stabilising floats being fixed, and a more powerful Mitsubishi MK4S Kasei 24 engine fitted to compensate for the increased drag.
Despite these problems, the E15K1 was ordered into limited production as the Navy Type 2 High-speed Reconnaissance Seaplane “Shiun” Model 11. Six were sent to Palau in the South Pacific, but these were quickly shot down by Allied fighters, as the jettisonable float failed to separate on demand (although subjected to wind tunnel testing, the float separation system had never been tested on the actual aircraft). This resulted in the cancellation of production in February 1944, with only 15 “Shiuns” completed, including the six prototypes (Ref.: 24).

POWER PLANT: Two Continental XI-1430-1 liquid-cooled engines, rated at 1,600 hp each

PERFORMANCE: 406 mph at 15,000 ft

COMMENT: The Lockheed XP-49 was a further development of the P-38 “Lightning” for a fighter in response to U. S. Army Air Corps proposal 39-775. Intended to use the new 24-cylinder Pratt & Whitney X-1800 engine, this proposal, which was for an aircraft substantially similar to the P-38, was assigned the designation XP-49, while the competing Grumman Model G-46 was awarded second place and designated XP-50 “Skyrocket”. Ordered in October 1939 and approved on January 8, 1940, the XP-49 would feature a pressurized cockpit and armament of two 20 mm (0.79 in) cannon and four .50 in (12.7 mm) machine guns. Two months into the contract, a decision was made to substitute the Continental XI-1430-1 (or IV-1430) for the X-1800. The XP-49 first flew on 11 November 1942. The prototype force-landed on 1 January 1943, when the port landing gear failed to lock down due to combined hydraulic and electrical system failures. The XP-49 next flew 16 February 1943, after repairs were made. Preliminary flight data showed performance was not sufficiently better than the production P-38, especially given the questionable future of the XI-1430 engine, to warrant disruption of the production line to introduce the new model aircraft. Consideration of quantity production was therefore abandoned (Ref.: 24).